Filters

2015 - 20192

More filters

20222
Reset filters

Settings

DDC: 500 × Subject: communication ×

Search Results

Now showing 1 - 2 of 2
  • Thumbnail Image
    Item
    Topological data analysis of contagion maps for examining spreading processes on networks
    ([London] : Nature Publishing Group UK, 2015) Taylor, Dane; Klimm, Florian; Harrington, Heather A.; Kramár, Miroslav; Mischaikow, Konstantin; Porter, Mason A.; Mucha, Peter J.
    Social and biological contagions are influenced by the spatial embeddedness of networks. Historically, many epidemics spread as a wave across part of the Earth’s surface; however, in modern contagions long-range edges—for example, due to airline transportation or communication media—allow clusters of a contagion to appear in distant locations. Here we study the spread of contagions on networks through a methodology grounded in topological data analysis and nonlinear dimension reduction. We construct ‘contagion maps’ that use multiple contagions on a network to map the nodes as a point cloud. By analysing the topology, geometry and dimensionality of manifold structure in such point clouds, we reveal insights to aid in the modelling, forecast and control of spreading processes. Our approach highlights contagion maps also as a viable tool for inferring low-dimensional structure in networks.
  • Thumbnail Image
    Item
    Modular coherent photonic-aided payload receiver for communications satellites
    ([London] : Nature Publishing Group UK, 2019) Duarte, Vanessa C.; Prata, João G.; Ribeiro, Carlos F.; Nogueira, Rogério N.; Winzer, Georg; Zimmermann, Lars; Walker, Rob; Clements, Stephen; Filipowicz, Marta; Napierała, Marek; Nasiłowski, Tomasz; Crabb, Jonathan; Kechagias, Marios; Stampoulidis, Leontios; Anzalchi, Javad; Drummond, Miguel V.
    Ubiquitous satellite communications are in a leading position for bridging the digital divide. Fulfilling such a mission will require satellite services on par with fibre services, both in bandwidth and cost. Achieving such a performance requires a new generation of communications payloads powered by large-scale processors, enabling a dynamic allocation of hundreds of beams with a total capacity beyond 1 Tbit s−1. The fact that the scale of the processor is proportional to the wavelength of its signals has made photonics a key technology for its implementation. However, one last challenge hinders the introduction of photonics: while large-scale processors demand a modular implementation, coherency among signals must be preserved using simple methods. Here, we demonstrate a coherent photonic-aided receiver meeting such demands. This work shows that a modular and coherent photonic-aided payload is feasible, making way to an extensive introduction of photonics in next generation communications satellites.